Data Project: Spatial Analysis of California Oil Spills

An example of my data science work where I visualize oil spill locations in California.

Sarah Hamilton true
2022-03-13

Introduction

The following code analyzes the frequency of inland oil spills in California in 2008. It uses spatial data of the California counties combined with spatial data of oil spill locations to visualize where oil spills occur most frequently. The oil spill location data came from the California State Geoportal as a part of their Oil Spill Incident Tracking.

hide 
knitr::opts_chunk$set(echo = TRUE, warning = FALSE, message = FALSE)

library(spatstat)
library(maptools)
library(raster)
library(tidyverse)
library(here)
library(sf)
library(tmap)

Exploratory Analysis of Oil Spills

hide 
# read in the data
spills <- read_sf(dsn = here(),
                  layer = "Oil_Spill_Incident_Tracking_[ds394]") %>%
  janitor::clean_names() %>%
  st_transform(crs = 32610)

county <- read_sf(dsn = here(),
                  layer = "california_county_shape_file") %>%
  janitor::clean_names() %>%
  select(name) %>%
  st_set_crs(4326) %>%
  st_transform(crs = 32610)

# exploratory plot 
# plot(spills)
hide 
# plot in tmap
tmap_mode("view")

tm_basemap(c(StreetMap = "OpenStreetMap",
             TopoMap = "OpenTopoMap")) +
  tm_shape(county) +
  tm_polygons(alpha = 0) +
  tm_shape(spills) +
  tm_dots(col = "#cc99aa")
hide 
  # tm_raster(midpoint = NA,
  #           palette = "Blues",
  #           legend.show = FALSE)

Figure 1: Interactive tmap of 2008 inland oil spill locations in California.

Oil Spills by County

hide 
# plot oil spills over counties
county_spills <- spills %>%
  group_by(localecoun) %>%
  summarize(total_spills = n(), na.rm = TRUE)

# merge county data with oil spill data
county_spills_density <- county %>%
  st_join(county_spills)

# plot data 
ggplot(data = county_spills_density) +
  geom_sf(aes(fill = total_spills),
          color = 'white', size = 0.1) +
  theme_minimal() +
  scale_fill_gradientn(colors = c("light blue", "dark blue")) +
  labs(fill = "Number of Oil Spills")

Figure 2: Choropleth map of 2008 inland oil spill locations in California. Inland oil spills are more common in the southern portion of California.

Data Citation: Oil Spill Incident Tracking [ds394]. 2020. California State Geoportal. https://gis.data.ca.gov/datasets/7464e3d6f4924b50ad06e5a553d71086_0/explore?location=36.752463%2C-119.422009%2C6.00&showTable=true.